mel jacobson on fri 23 feb 07
firing any kiln leads us all into personal systems. we are what we are.
many people become lead by traditions and systems that
are `made up` by others. you must find a system that works
best for you.
safety and close inspection of your system during the
firing is critical.
i like to have gobs of time out in front of me. no
schedule of places to be, a movie at 7:15, the symphony
with friends at 8:00 p.m.
so this is my schedule.
made for me, with lots of safety in place.
i load my big gas kiln late in the afternoon. i listen
to a clever radio guy...laugh a bit, organize my glazed pots.
it take about 90 minutes to load.
i take my time...but, keep at it.
make sure kiln shelves are staggered....rotate the advancers
with the sil/carbide. lots of room. brick in the door.
lite the small pre/heat burner.
this is all `RITUAL`.
THE SAME, EVERY TIME.
the pre/heat system is just there...because i was bisque firing
years ago...and needed a very slow pre/heat. that is why the
small burner is part of my kiln. all of the water vapor leaves the kiln
over night...wax burns off, i open the damper about a half inch so
the kiln vents out the stack. this of course heats the stack and
makes sure everything is going in the `right direction`...up the stack.
i get up at 4 a.m. use a burnzomatic torch and heat the flue/damper
area, make certain there is no unburned gas back there...just a precaution,
but i
always do it. it takes less than a minute.
i then lite the pilots on both burners/set the baso valves. open the damper
all the way...turn the kiln on with maximum gas pressure/wide open.
away she goes.
i put the kiln in lite reduction about cone 08. i have 1750f marked on
my pyrometer. shino has me starting at cone 011.
i make certain i have two inches of back pressure from my main
cone port. i let her rip.
as soon as the kiln reaches the low 2000's i pull back the gas pressure.
in fact, the more i turn it down, the hotter it gets.
the dance is controlling the damper, the back pressure and the
gas pressure. how much primary air gets to the burners is also
critical. it varies...as to how much reduction i need.
i have five fans running around my kiln...lots of soft air movement.
i have a solid door that i close into my studio. i never let kiln room
air enter the studio. i vent with a gravity/air system out the ceiling
and have a motor driven large vent behind the stack.
windows wide open. lots of air movement around the kiln, and
good venting. i do not get headaches when i fire. (the first sign of
carbon m poisoning)
i love the early morning hours for the first part of the firing.
no phone, no door bell, no one up but me. i am alone with the
kiln. i read, make clay...mess about the studio. stare at the wall.
i fire til it is done. cone 10 for me is the tip of cone 10 at six o'clock.
or, touching the shelf. cone 11 is at 2:30. (remember, there is a very short
span of heat between 10 and 11. just a few degrees.
when cone ten is moving, i open the damper all the way, open up
the primary air and clear the kiln. the kiln really jumps in heat at
this time....i have to be close...as the cone 10 plummets. i keep an
oven timer...set at 10 minute intervals. i always use it.
when the kiln is done...i wait one hour...and add small sticks through
the burner ports. things smoke...this takes about 10 minutes.
RITUAL. there is no scientific evidence that this does
anything...who cares? it is my kiln.
i do not depend on kiln gods...i depend on mel to do things right.
good science/technique kicks the crap out of kiln gods every time.
at about 1900f i put one burner back on for at least 90 minutes.
hold the kiln, or let it rise just a bit. oxidize..no reduction.
i am all done with all of this by late afternoon.
have a nice supper.
relax. go to bed early.
peek the next morning at 9.
unload in the afternoon.
when i see people loading a kiln at 4 in the afternoon, knowing the
kiln goes on right away...and they will be firing until 3 a.m. i shudder.
when they get tired, drink a few beers...and the kiln stalls, everything
goes to hell. bad decisions are made....it is dangerous, and often
the kiln gets shut down before it is done. they have wasted time,
valuable heat energy, and they get crappy pots.
then they do it the same way the next month. bad ritual.
mel
from: mel/minnetonka.mn.usa
website: http://www.visi.com/~melpots/
Clayart page link: http://www.visi.com/~melpots/clayart.html
Pamela Regentin on fri 23 feb 07
Mel,
This was a wonderful post, very helpful. Thanks for taking the time to post it. I have one question: why do you heat the kiln for 90 minutes after it cools to 1900f? What is the effect you are achieving with that technique?
Is there any one out there reading who has an updraft? With atmospheric burners? It would be so helpful to me in learning how to fire my kiln properly and get good glaze reduction if someone could post something similar to Mel's post about the firing of an updraft. I am particularly in need of learning how to get good reduction without wasting fuel.
I have high fired my updraft once now. I followed advice from a Nils Lou book and the one titled "Gas Kiln Firing" (author escapes me at the moment). Things went really well (except when I thought we stalled at ^5 according to the pyrometer, only to see ^8 go down and figure out my pyrometer had quit!) and I got good body reduction. Glaze reduction wasn't so great. All the shino tests from various parts of the kiln were white. Part of my problem is not having a good iron body yet though. I did the "char test" which indicated reduction, had lots of back pressure, etc. A friend suggested I need to stack the kiln really tight, even putting pots in the vacant space between the burners and shelves, to eliminate some of the oxygen potential in a reducing atmosphere.
Thanks to anyone willing to take the time to help me out!
Pam
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Victoria E. Hamilton on fri 23 feb 07
Pam -
I fire a 40-year old Alpine updraft weekly.
You can reach me at 206.779.9483.
I'd be happy to help if I can.
Vicki Hamilton
Millennia Antica Pottery
Seattle, WA
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Pamela Regentin
Sent: Friday, February 23, 2007 5:24 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: [CLAYART] firing systems/preheat/style
Mel,
This was a wonderful post, very helpful. Thanks for taking the time to post
it. I have one question: why do you heat the kiln for 90 minutes after it
cools to 1900f? What is the effect you are achieving with that technique?
Is there any one out there reading who has an updraft? With atmospheric
burners? It would be so helpful to me in learning how to fire my kiln
properly and get good glaze reduction if someone could post something
similar to Mel's post about the firing of an updraft. I am particularly in
need of learning how to get good reduction without wasting fuel.
I have high fired my updraft once now. I followed advice from a Nils Lou
book and the one titled "Gas Kiln Firing" (author escapes me at the moment).
Things went really well (except when I thought we stalled at ^5 according to
the pyrometer, only to see ^8 go down and figure out my pyrometer had quit!)
and I got good body reduction. Glaze reduction wasn't so great. All the
shino tests from various parts of the kiln were white. Part of my problem is
not having a good iron body yet though. I did the "char test" which
indicated reduction, had lots of back pressure, etc. A friend suggested I
need to stack the kiln really tight, even putting pots in the vacant space
between the burners and shelves, to eliminate some of the oxygen potential
in a reducing atmosphere.
Thanks to anyone willing to take the time to help me out!
Pam
---------------------------------
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Gail Dapogny on sat 24 feb 07
I, too, loved what Mel wrote. It rang so true.
It brought back memories of a time a couple of years ago when I was
firing the last few hours of our kiln, and found that the cones were
nowhere to be seen. Absolutely out of sight. I was firing the last
few hours, and found myself nervously checking color and sound in a
way that I'd never done before. I remember at some point saying to
the kiln, "Come on , baby, help me out here; I'm just not sure when
you are going to be ready to be turned off". (This is a 95 cubic
foot kiln with hundreds of pots in it of various guild members and
students. It fires for 12-13 hours after warming up. It's a
responsibility, to be sure. )
Every time i decided to turn her off (by that time she somehow seemed
feminine), something would hold me back, and I'd give her a little
more time. Finally I turned her off.; it just felt right. We fire
our kiln to cone 9 down, and 10 half over. When we unloaded her 36
hours later, the cones were exactly right on, and the kiln was
beautiful.
Looking back, I felt as though the kiln and I were great friends, and
that she guided me into greater patience. She's an old kiln -- at
least 50 years old (don't know what that is in kiln years!), JT
built; has had several surgeries which she survived well. When you
treat her lovingly, she almost fires herself. For me, she's an old
friend.
Gail Dapogny in Ann Arbor
On Feb 23, 2007, at 5:43 AM, mel jacobson wrote:
> i liked lee's idea that kilns have a language.
> you have to learn it.
>
> many never have the time to learn a new language, they
> just use a book of translation. ja/be/kee
>
> many fire kilns that way.
>
> my kiln talks. it tells me things...and, i have to
> react to what she is saying.
> it is female..for sure.
> and, i do listen.
>
> she smells certain ways, she talks, and she sings. it is a dance.
> she leads.
>
> the sound of burners, the rush of air up the stack, the color inside.
> the atmosphere swirling. it is kiln language. you can only learn
> the language by immersion.any kiln will have a perfect balance.
> you can feel it. it just chugs.some people have never found their
> kilns balance point.if it stalls, just jack up the heat some more.
> give it more of the foot pedal...to the floor. probably the wrong
> thing to do.turn it down. but, do something. listen to the sound,
> smell the smell,listen.
>
>
Pamela Regentin on sun 25 feb 07
I knew before reading all the firing poetry what a fuel burning kiln would require of me. I've only fired my kiln once but it was by far the most fun and biggest challenge I've ever had firing. I did it all myself which was very satisfying also.
All the things that were described so eloquently (language, dancing, etc.) I sensed in the kiln that one time. I'm anxiously getting ready for the next time we are paired together.
I have waited twenty years for my own gas kiln. I've been a potter for twenty seven years but for many reasons could only have an electric kiln (cost, place, life circumstances) and longed for a gas kiln and reduction fired pots. I had intervals of firing work in friends' kilns, firing work in an anagama as a guest, but waiting, sometimes impatiently, for my own fire. I was planning to build a kiln and consternated by how difficult that prospect was with so many choices and kiln styles. My wait ended unexpectedly last year with the opportunity to buy a used updraft. (The previous potter-owner was a local man I know who had to close his studio because of his Alzheimers...) It took four months to get the kiln installed and running. The first time I lit up the burners for my husband to see what was in store was exhilarating for me and terrifying for him. I set a date for the first fire and sent out invitations for a kiln opening party, trying to explain in them why this event
required a celebration.
Mel said:>>> the sound of burners, the rush of air up the stack, the color inside.
> the atmosphere swirling. it is kiln language. you can only learn
> the language by immersion<<<
So yes, I knew this, sensed it and somewhat feared it. It's a process that I'm supposed to guide and direct but with little experience. Too much can go wrong if done badly. How am I supposed to learn that language unless I have a translator? How many pots do I ruin and time (and fuel) do I waste? Nobody wants to dance and crush toes every time. I want to learn. So I'm reading books and picking brains. And I'll be firing while taking copious notes. I'm preparing for my participation in an artist's open studio tour in April. I hope to have a few "keepers" out of the fire!
So I had my first kiln opening celebration. Six of my seven kids were there, just as excited as I. They brought friends. My brothers, sil, dh, potter friend. Only my potter friend knew what it really means to open a kiln after a firing. I tried to educate the crowd huddled in my 40degree kiln studio what went on in the kiln and what signs I was looking for in the results. I hadn't put any "good" work in the stack, and lots of test pieces, so I told them not to expect any masterpieces. They all oohed and ahhed over every piece that came out (and wanted to take stuff home "sorry that's a test, I need to write some notes..") and were quite excited about it all. All that family support felt nice. We ended the evening with a big pot of smoked salmon chowder and some micro-brews, wine and prize-winning apple pie (literally. My pies have won $2000 in prize money...) It was a fun time but somewhat anti-climatic. The most exciting time was definately the firing day.
I learned a lot. All the blistery, runny test pieces gave me direction. I know what I want to try next.
So, I'm anxiously awaiting the day when I do it again...soon.
Pam
Gail Dapogny wrote: I, too, loved what Mel wrote. It rang so true.
It brought back memories of a time a couple of years ago when I was
firing the last few hours of our kiln, and found that the cones were
nowhere to be seen. Absolutely out of sight. I was firing the last
few hours, and found myself nervously checking color and sound in a
way that I'd never done before. I remember at some point saying to
the kiln, "Come on , baby, help me out here; I'm just not sure when
you are going to be ready to be turned off". (This is a 95 cubic
foot kiln with hundreds of pots in it of various guild members and
students. It fires for 12-13 hours after warming up. It's a
responsibility, to be sure. )
Every time i decided to turn her off (by that time she somehow seemed
feminine), something would hold me back, and I'd give her a little
more time. Finally I turned her off.; it just felt right. We fire
our kiln to cone 9 down, and 10 half over. When we unloaded her 36
hours later, the cones were exactly right on, and the kiln was
beautiful.
Looking back, I felt as though the kiln and I were great friends, and
that she guided me into greater patience. She's an old kiln -- at
least 50 years old (don't know what that is in kiln years!), JT
built; has had several surgeries which she survived well. When you
treat her lovingly, she almost fires herself. For me, she's an old
friend.
Gail Dapogny in Ann Arbor
On Feb 23, 2007, at 5:43 AM, mel jacobson wrote:
> i liked lee's idea that kilns have a language.
> you have to learn it.
>
> many never have the time to learn a new language, they
> just use a book of translation. ja/be/kee
>
> many fire kilns that way.
>
> my kiln talks. it tells me things...and, i have to
> react to what she is saying.
> it is female..for sure.
> and, i do listen.
>
> she smells certain ways, she talks, and she sings. it is a dance.
> she leads.
>
> the sound of burners, the rush of air up the stack, the color inside.
> the atmosphere swirling. it is kiln language. you can only learn
> the language by immersion.any kiln will have a perfect balance.
> you can feel it. it just chugs.some people have never found their
> kilns balance point.if it stalls, just jack up the heat some more.
> give it more of the foot pedal...to the floor. probably the wrong
> thing to do.turn it down. but, do something. listen to the sound,
> smell the smell,listen.
---------------------------------
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Larry Kruzan on sun 25 feb 07
Hi Pam,
Congratulations! There is nothing better than the smell of a good reduction
- except good friends and family to share it with. (Good food doesn't hurt
either - apple pie!!!! - yum yum!!)
Larry Kruzan
Lost Creek Pottery
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